Electrode catheters have been in common use in medical practice for many years. They are used to stimulate and map electrical activity in the heart and to ablate sites of aberrant electrical activity. In use, an electrode catheter is inserted into a major vein or artery, e.g., femoral artery, and then guided into the chamber of the heart which is of concern. The catheter should preferably be deflectable to permit proper positioning of the electrodes on its distal end within the heart.
Deflectable tip electrode catheters are well known. Such a catheter generally has a control handle at its proximal end for controlling deflection of the tip in one or more directions. For example, a particularly useful deflectable tip catheter is disclosed in U.S. Pat. No. Re. 34,502 to Webster, the disclosure of which is hereby incorporated by reference. This catheter comprises a puller wire that extends on-axis through an elongated reinforced catheter body and then off-axis in a deflectable tip portion. In this arrangement, longitudinal movement of the puller wire relative to the catheter body results in deflection of the catheter tip portion. Other examples of steerable catheters can be found in U.S. Pat. No. 5,431,168 to Webster entitled “Steerable Open-Lumen Catheter” and U.S. patent application Ser. No. 08/924,611 to Webster entitled “Omni-Directional Steerable Catheter,” the disclosures of which are hereby incorporated by reference.
One drawback to catheters and perhaps especially deflectable catheters is the difficulty of maintaining a catheter in position while in the patient's body. That is, once a suitable tissue site has been located for treatment or evaluation, such as mapping, ablation or the like, the physician is often caught in a predicament with maintaining at least one hand on the catheter while attempting to record or otherwise mark the location of the tissue site. The problem may be greater with deflectable catheters which can store torsional energy and therefore unwind and shift when released from the doctor's grasp. With the heart chamber being a dynamic environment surrounded by moving tissue and blood flow, the target site, which may be relatively small to begin with, can be readily lost with the slightest movement in the catheter.
Because a catheter is typically used with an introducer or a sheath which facilitates the catheter's entry into the patient's body via a valve, it would be desirable to provide a catheter grip that attaches to the valve. Often with one hand already working the introducer or sheath, an attending doctor could then readily use that same hand to operate the catheter grip. Moreover, it would be desirable to bias the grip toward a closed or gripping configuration so that actuation of the grip involves minimal action on behalf of the doctor.